Hwan Woon-ryong and Beom Pung-ho have spent their entire lives as bitter rivals, each standing as the heir to one of the world’s most powerful crime syndicates. Their hostility is deeply rooted, fueled by years of competition. Just as they are about to secure the biggest opportunity of their careers, everything takes an unexpected turn when a toddler named Hwan Beom-hae appears—confirmed through advanced DNA testing to be the biological child of both of them. Shocked and confused, the two are given a bizarre yet high-stakes condition: they must raise Beom-hae together with care and responsibility. In return, they will gain exclusive rights to a massive global construction project approved by the United Nations. However, working together proves far from easy when they can barely tolerate each other, let alone share parenting duties. As they navigate daily challenges and the demands of raising a child, Beom-hae slowly begins to break down the walls between them, bringing unexpected changes to their dynamic. The question remains whether these longtime enemies can overcome their differences—or if their unresolved tension will ruin everything.